Path constraint solving based test generation for observability-enhanced branch coverage

Yanhong Zhou, Huawei Li, Tiancheng Wang, Bo Liu, Yingke Gao, Xiaowei Li

Abstract: Traditional coverage metrics in verification focus on controllability without taking observability into account, which may result in an artificially high coverage and a false sense of confidence. In this paper, we present a path constraint solving based test generation method at register-transfer level (RTL) for observability-enhanced branch coverage. The branches executed but not observed by a test sequence are identified as our target branches. The test generation for each target branch is converted to the process of covering multiple intermediate sub-target states sequentially to guarantee the execution and observation of the target branch. Valid input vectors are automatically generated by multicycle path constraint solving and simulation is guided by the abstract distance information to reach the sub-target states. Experimental results show that our approach can reduce the gap between branch coverage and observability-enhanced branch coverage.

External IDs:dblp:conf/vts/ZhouLWLGL16